1. Field of the Invention
The present invention relates to improvements in an apparatus for detecting pulse wave produced from an arterial vessel of a living body.
2. Related Art Statement
The Assignee to which the present U.S. patent application is assigned, previously filed Japanese Utility Model Application No. 62-93846 on June 18, 1987 in which they disclose a pulse wave detecting apparatus having (a) a pulse wave sensor which is pressed against a body surface over an arterial vessel so as to detect pulse wave produced from the artery, and (b) pressing means for pressing the pulse wave sensor against the body surface with an optimum pressing force, the optimum pressing force being determined based on pulse wave signal produced by the pulse wave sensor while the pressing force of the pressing means is varied, so that the magnitude of the pulse wave signal is optimized.
The above pulse wave detecting apparatus operates normally so that the pressing force of the pressing means is optimized, on the condition that the pulse wave sensor has already been placed on the body surface of a subject. However, if the pressing means is activated to press the pulse wave sensor though the sensor has not been contacted with the body surface, the pressing means is operated until pulse wave signal is produced from the sensor. In such case, the pulse wave sensor is displaced an excessively large operation amount or stroke by the pressing means. This tends to cause a mechanical breakdown or failure in the apparatus.